1. Technical Field
The present invention relates to a robot, a controller, and a robot system.
2. Related Art
In the related art, a robot system including a robot that includes a robot arm and a controller that controls the robot has been known. The robot arm includes a plurality of arms (arm members) coupled with one another through joints, and, for example, a hand is attached as an end effector to the arm on the distal-most end side (the downstream-most side). The joints are driven by motors, and the arm rotates by the driving of the joint. Then, the robot grips, for example, an object with the hand, moves the object to a predetermined place, and performs predetermined work such as assembly.
Moreover, each of the motors is provided with an encoder that detects the rotation angle of the motor. A dedicated signal line (wire) is connected to each of the encoders, and the signal lines are connected to the controller. The controller controls the robot arm based on detection results of the encoders.
JP-A-11-175118 discloses a controller of a robot in which a plurality of encoders provided in a robot arm are connected in a multidrop manner on a common serial bus. In this controller, the number of signal lines with respect to the encoders can be reduced.
However, since the number of encoders and the number of signal lines are the same as each other in the robot in the related art and the number of signal lines is large, the robot arm becomes thick. This leads to a problem of increasing the size of the robot and increasing the weight thereof.
Moreover, in the controller disclosed in JP-A-11-175118, multiplexing of the encoder and a different sensor such as an angular velocity sensor is not performed. For this reason, when a different sensor is provided in the robot arm, the number of signal lines increases and thus the robot arm becomes thick. This leads to a problem of increasing the size of the robot and increasing the weight thereof.